Sanding belt runs off pulleys

Sanding belt runs off pulleys

Post by Gary Beye » Sat, 09 Aug 1997 04:00:00



I have a very old Delta Finishing Machine with a 12" disk and 4x52
horizontal belt. It's a great heavy duty machine that I use for both
wood and metalworking. The problem is I can't seem to keep the belt in
the center of the pulleys. Quite the opposite, it is very dificult to
keep it on. The machine has fine pitch adjustments for both tension and
pulley angle, but if I'm able to make it run true, it will walk off as
soon as I press the work to it. Is this just characteristic of the
machine, or am I missing something here? BTW, there are no protruding
rims on the pulleys.

 
 
 

Sanding belt runs off pulleys

Post by sam cole » Sun, 10 Aug 1997 04:00:00


Quote:

> That indicates that at least one of the pulley has additional wear on
> one end or the other (the ends are no longer the same size).  Delta
> stocks parts for machines as old as in the 40's, so they should be able
> to sell you a pulley.  You might want to break the machine down and
> check the bearings while you are measuring the ends of the pulley to
> determine which one is faulty (hopefully not both).


> > I have a very old Delta Finishing Machine with a 12" disk and 4x52
> > horizontal belt. It's a great heavy duty machine that I use for both
> > wood and metalworking. The problem is I can't seem to keep the belt in
> > the center of the pulleys. Quite the opposite, it is very dificult to
> > keep it on. The machine has fine pitch adjustments for both tension and
> > pulley angle, but if I'm able to make it run true, it will walk off as
> > soon as I press the work to it. Is this just characteristic of the
> > machine, or am I missing something here? BTW, there are no protruding
> > rims on the pulleys.

Dont overlook a defective sanding belt, or possibility of loose pulley
mounting. Experiment by putting a turn or more wide masking tape around
different places on one or other/both pulleys. If there is adjustment of
belt tension try changing that, probably more.
Good luck- Sam

 
 
 

Sanding belt runs off pulleys

Post by Tangen » Mon, 11 Aug 1997 04:00:00


Hi Gary.

1.  Perform  the checks that Tom suggested.

2.  When checking for ware keep in mind that the fixed pully is not
supposed to be a perfect cylinder. It needs to have a gentle curve. (IE
larger in the centre and smaller on the outer edges).
The curve in the pully is the main thing that keeps the belt on and
considering the age of the machine this pully may have worn to one side or
worn flat resulting in belt wander.

3.  The adjustable pully should be cylindrical.

4. If the backing plate that the belt slides over is worn concave this may
contribute to your problems

 
 
 

Sanding belt runs off pulleys

Post by Peter Dru » Tue, 12 Aug 1997 04:00:00



:->2.  When checking for ware keep in mind that the fixed pully is not
:->supposed to be a perfect cylinder. It needs to have a gentle curve. (IE
:->larger in the centre and smaller on the outer edges).
:->The curve in the pully is the main thing that keeps the belt on and
:->considering the age of the machine this pully may have worn to one side or
:->worn flat resulting in belt wander.
:->
:->3.  The adjustable pully should be cylindrical.

It doesn't really make any difference, as long as one pulley is flat
and one has a crown, it'll work. My old Craftsman(c.1970) belt sander
has the crown on the adjuster pulley.


Using OS/2 Warp 4!
Wausau, WI. 44d 58m 00s N x 89d 36m 45s W
All opinions are mine alone, you go get your own!

 
 
 

Sanding belt runs off pulleys

Post by Keith Bo » Tue, 12 Aug 1997 04:00:00


Tangent,

If I'm not mistaken the "drive" pulley on this sander should be a true
cylinder.  The "idler" pulley is crowned to allow for belt tracking.

Keith Bohn
Bohn & Bonn Design



Quote:
>Hi Gary.

>1.  Perform  the checks that Tom suggested.

>2.  When checking for ware keep in mind that the fixed pully is not
>supposed to be a perfect cylinder. It needs to have a gentle curve. (IE
>larger in the centre and smaller on the outer edges).
>The curve in the pully is the main thing that keeps the belt on and
>considering the age of the machine this pully may have worn to one side or
>worn flat resulting in belt wander.

>3.  The adjustable pully should be cylindrical.

>4. If the backing plate that the belt slides over is worn concave this may
>contribute to your problems

 
 
 

Sanding belt runs off pulleys

Post by Martin H. Eastbur » Tue, 12 Aug 1997 04:00:00


Quote:

> Tangent,

> If I'm not mistaken the "drive" pulley on this sander should be a true
> cylinder.  The "idler" pulley is crowned to allow for belt tracking.

> Keith Bohn
> Bohn & Bonn Design

Tangent,

We are assuming you know about the knurled nut on the other side of the
opening for the belt. This adjusts cw-ccw to adjust tracking.
Every time you put on a new belt, this needs to be adjusted, and
sometimes
after some ware.  I usually only do it once.

This changes the 'main-line' angle between the drive wheel and idler
wheel.
My front wheel is groved and I think domed.  The rear wheel is round
and has a black tire on it for friction.
(This info is just incase you have a new tool, and don't know after the
first belt)

Otherwise, - is it possible that this adjusting***has been
mal-adjusted
by a little one - looking at what dad was doing ; so it doesn't work
like
it has for years ?

How about something small stuck to the rear tire - that you can't see -
it pitches the belt off center.

Martin

 
 
 

Sanding belt runs off pulleys

Post by Ken Kanar » Tue, 12 Aug 1997 04:00:00


Quote:

>  The machine has fine pitch adjustments for both tension and
> pulley angle, but if I'm able to make it run true, it will walk off as

> soon as I press the work to it.

Something must be loose or worn so the pulley is moving out of alinement
when you press the work to it.
 
 
 

Sanding belt runs off pulleys

Post by Star Spangl » Wed, 13 Aug 1997 04:00:00


Have you tried a new belt? Sometimes a belt will remember the curve of
the pulleys and never run true again. This happens when left idle for
long periods. I have had this same problem and with a belt change and
a good cleaning of the pulleys it seems to help.

On Fri, 08 Aug 1997 15:10:28 -0500, Gary Beyer

Quote:

>I have a very old Delta Finishing Machine with a 12" disk and 4x52
>horizontal belt. It's a great heavy duty machine that I use for both
>wood and metalworking. The problem is I can't seem to keep the belt in
>the center of the pulleys. Quite the opposite, it is very dificult to
>keep it on. The machine has fine pitch adjustments for both tension and
>pulley angle, but if I'm able to make it run true, it will walk off as
>soon as I press the work to it. Is this just characteristic of the
>machine, or am I missing something here? BTW, there are no protruding
>rims on the pulleys.

------------------------------------------
Minichillo's Repair and more

remove the x before and after for replies
http://www.dreamscape.com/pminchlo
------------------------------------------
 
 
 

Sanding belt runs off pulleys

Post by Gary Beye » Wed, 13 Aug 1997 04:00:00


Quote:

> Hi Gary.

> 1.  Perform  the checks that Tom suggested.

> 2.  When checking for ware keep in mind that the fixed pully is not
> supposed to be a perfect cylinder. It needs to have a gentle curve. (IE
> larger in the centre and smaller on the outer edges).
> The curve in the pully is the main thing that keeps the belt on and
> considering the age of the machine this pully may have worn to one side or
> worn flat resulting in belt wander.

> 3.  The adjustable pully should be cylindrical.

> 4. If the backing plate that the belt slides over is worn concave this may
> contribute to your problems

Well, now I have some 'fessing up to do. When I got the machine, the
drive pulley was grooved and worn and was very easy to "true up" with a
file while the motor was running. Sounds like I made a mistake making it
flat.  :(

Can someone tell me about how much crown should be on the pulley? I
checked Delta and most of the parts are no longer stocked...

 
 
 

Sanding belt runs off pulleys

Post by Robert Kle » Thu, 14 Aug 1997 04:00:00


Wrap some masking tape around the center of one of the drums to give a
crown.  The belt will stay put.

As to the fault in the machinery, sorry but I cannot help there.

Quote:

>I have a very old Delta Finishing Machine with a 12" disk and 4x52
>horizontal belt. It's a great heavy duty machine that I use for both
>wood and metalworking. The problem is I can't seem to keep the belt in
>the center of the pulleys. Quite the opposite, it is very dificult to
>keep it on. The machine has fine pitch adjustments for both tension and
>pulley angle, but if I'm able to make it run true, it will walk off as
>soon as I press the work to it. Is this just characteristic of the
>machine, or am I missing something here? BTW, there are no protruding
>rims on the pulleys.

Regards,

Robert Klein
Robert's Antiques and Restoration
2500 North T Street
Pensacola, FL  32505  USA



 
 
 

Sanding belt runs off pulleys

Post by Gary Beye » Sat, 16 Aug 1997 04:00:00


Thanks for to all of you for your help on this, especially Sam Coley,
who suggested putting a crown on the pulley with masking tape. Works
like a dream, and it may be the permanent fix since the edges of the
pulley are less than an eigth inch thick. I imagine the tape will last
for quite some time and it would be pretty cheap and easy to replace!